Overall, while confirmed SARS-CoV-2 infections were clearly associated with increased levels of SARS-CoV-2/CCCoV N- and S-specific IgG and IgM Abs, SARS-CoV-2 vaccination alone also seemed to boost these Ab levels, but mild/asymptomatic SARS-CoV-2/CCCoV infections (not diagnosed) could also contribute to these results. Here, CD40LG is linked to infection.